Transformation zone at the vallate papillae: a significant source of papillomavirus infection at the base of the tongue?

Objective: The aim of this study was to investigate whether the base of the tongue harbours a transformation zone (TZ), i.e., an initiation site for papillomavirus infection, analogous to that in the uterine cervix by examining the histological structure of Von Ebner's gland ducts in the vallate papillae.

Methods: Immunohistochemical staining and immunofluorescence techniques were used to detect markers associated with the uterine cervical TZ in the vallate papillae, and these results were compared with those in uterine cervical tissue. Additionally, tongue samples from mouse papillomavirus (MmuPV1)-infected mice were analysed to test our hypothesis.

Results: The specific expression of CK17 in the squamous epithelium of the vallate papillae indicated the presence of immature squamous epithelium, arising from the transformation of reserve cells in this region. Moreover, a s determined using virus-infected mice, the TZ at the base of the tongue was a significant site for papilloma virus infection.

Conclusions: This is the first study to reveal the presence of a TZ in the vallate papillae, as determined by the presence of reserve cells and immature squamous epithelium, suggesting that the base of the tongue is a significant site for papillomavirus infection. This finding provides an entry point for the early prevention and diagnosis of HPV-associated lesions in the oropharynx.